Pharmaceutical composition comprising amorphous lenalidomide and an antioxidant

ABSTRACT

The present invention relates to a pharmaceutical composition comprising amorphous lenalidomide, or a pharmaceutically acceptable salt thereof, with a synthetic antioxidant and one or more pharmaceutically acceptable excipients. The invention further relates to the process to manufacture such a compositions and the use of said composition as a medicament, particularly in the treatment of in the treatment of multiple myeloma and myelodyplastic syndromes.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a bypass Continuation of PCT/EP2016/082318filed on Dec. 22, 2016, which claims priority of EP15202069.9 filed Dec.22, 2015, the entire contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

Lenalidomide, chemically (RS)-3-(4-Amino-1-oxo1,3-dihydro-2H-isoindol-2-yl)piperidine-2,6-dione of formula (I),

is a pharmaceutically active compound used for the treatment of multiplemyeloma and Myelodysplastic syndromes.

The compound was discovered by Celgene and is disclosed in EP925294.Lenalidomide is the active ingredient in the medicinal product soldunder the brand name Revlimid®.

Lenalidomide exhibits polymorphism. WO2005023192 discloses crystallineforms of lenalidomide, its process of preparation, compositionscomprising these crystalline forms and its use for treatment ofdiseases. Polymorph B is the most stable form and is present in themarketed tablets. Compositions comprising both amorphous and crystallinelenalidomide are also disclosed in this application. Other polymorphicforms of lenalidomide are disclosed in WO2011111053. The prior art thusteaches that lenalidomide crystallizes very easily. Moreover, it wasexperienced in our laboratory that polymorphic transitions oflenalidomide take place rather easily, especially in drug product.

Lenalidomide is slightly soluble in water. Conventional approaches toincrease solubility consist on micronizing the API. Nevertheless, it wasexperienced in our laboratory that micronization of lenalidomide gavepartially amorphous solid, which readily converts to other crystallineforms. It is known that generally the solubility of amorphous forms ishigher compared to the solubility of crystalline forms. In view of this,it would be desirable to produce stable amorphous lenalidomide and tofind a robust process for making such a stable amorphous lenalidomide.

WO2010054833 and WO2009114601 disclose solid dispersions containingamorphous lenalidomide.

It has been found that amorphous lenalidomide generates more impurities,especially oxidative impurities, if compared with the crystallinelenalidomide, making the use of amorphous lenalidomide in a commercialscale very difficult.

Revlimid® is in the market as a crystalline form, the marketformulation, which has been submitted to extended stability studies doesnot contain an antioxidant.

WO2010061209 relates to new crystalline forms of lenalidomide in thedescription it is mentioned that preservatives and chelatings agents maybe added to improve storage stability. This application however does notsuggest that the replacement of crystalline lenalidomide for amorphouslenalidomide will result in additional stability problems.

Thus in view of the stability problems of amorphous lenalidomide, thereis a need for pharmaceutical compositions comprising amorphouslenalidomide, or a pharmaceutically acceptable salt thereof, which arestable and suitable for use on a commercial scale.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a pharmaceutical composition comprisingamorphous lenalidomide, or a pharmaceutically acceptable salt thereof,with a synthetic antioxidant and one or more pharmaceutically acceptableexcipients.

It also provides a process for preparing said amorphous lenalidomidecomprising the steps:

-   -   a) Dissolving lenalidomide or a pharmaceutically acceptable salt        thereof with a polymer and a synthetic antioxidant;    -   b) Spray or spray drying the solution of step a) on a carrier to        obtain a granule;    -   c) Blending the granule with further excipients;    -   d) Optionally encapsulating the blend of step c.

An alternative process to manufacture the amorphous lenalidomidecompositions of the present invention comprises the steps:

-   -   a) Dissolving lenalidomide or a pharmaceutically acceptable salt        thereof with a polymer;    -   b) Spray or spray drying the solution of step a) on a carrier to        obtain a granule;    -   c) Blending the granule with a synthetic antioxidant and further        excipients;    -   d) Optionally encapsulating the blend of step c.

Said pharmaceutical composition may be used as a medicament,particularly in the treatment of multiple myeloma and myelodyplasticsyndromes.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a pharmaceutical composition comprisingamorphous lenalidomide, or a pharmaceutically acceptable salt thereof,with a synthetic antioxidant and one or more pharmaceutically acceptableexcipients.

Drugs that can exist in either amorphous or crystalline form tend tocrystallize over time when present in amorphous state because thecrystalline form of the drug is a lower-energy state than the amorphousform.

WO2010/061209 suggests that preservatives and chelatings agents may beadded to their crystalline polymorph lenalidomide compositions toimprove storage stability.

Crystalline lenalidomide is in the European market since 2007 asRevlimid®. This commercial formulation does not contain antioxidants. Inorder to get approved by EMA (European medicines agency), a drug has tocomply with the guidelines and has to be submitted to a thoroughstability testing program, including stress testing. The scientificassessment of Revlimid by the EMA (26 Jun. 2007) stated that all resultsremained within the specification. Therefore, it can be concluded thatthe crystalline marketed lenalidomide does not present oxidationproblems.

It was surprisingly found that the replacement of crystallinelenalidomide for amorphous lenalidomide has a negative influence on thechemical stability of the compound. In particular oxidative degradationof the amorphous lenalidomide has been observed. This occurs even when ahigh protective packaging as Al/Al is used. The increase of theseoxidatives impurities is inherent to the amorphous form and it is notseen with other forms as Form A or B (these polymorphs are described onWO2005023192).

Degradation of the amorphous lenalidomide affects the stability of thepharmaceutical preparation, making it difficult to be used in acommercial scale. The observed oxidative degradation of amorphouslenalidomide was unexpected as the dry crystalline form is known to bevery stable.

Accordingly it would be desirable to provide a pharmaceutical amorphouslenalidomide which has a higher solubility than the crystallinelenalidomide composition but is less prone to oxidative degradation.

As used herein, the term oxidative degradation refers to a chemicalreaction of lenalidomide with oxygen during manufacture and/or storageproducing oxidative impurities.

A method for avoiding the oxidative impurities is to use a highprotective packaging material such as Al/Al. However, the inventorsfound that this package was not preventing the formation of oxidativedegradation.

Another method to prevent oxidative degradation is the use ofantioxidants.

Antioxidants are substances added in small quantities to hydrocarbonswhich are susceptible to oxidation. Antioxidants work in different ways.Antioxidants can be natural for instance ascorbic acid, vitamin E,tartaric acid or citric acid or synthetic. The synthetic antioxidantscan be classified in primary and secondary antioxidants. In primaryantioxidants (also called free-radical scavengers), antioxidativeactivity is implemented by the donation of an electron or hydrogen atomto a radical derivative. These antioxidants are usually hindered amines(p-Phenylene diamine, trimethyl dihydroquinolines, alkylated diphenylamines) or substituted phenolic compounds with one or more bulkyfunctional groups such as a tertiary butyl at 2,6 position commonly.Butylated hydroxytoluene (BHT) is a common example of hindered phenolicantioxidant. Primary antioxidants are free radical scavengers whichcombine with peroxy radicals and break autocatalytic cycle. In secondaryantioxidants (also called peroxide decomposers), activity is implementedby the removal of an oxidative catalyst and the consequent prevention ofthe initiation of oxidation. Examples of peroxide decomposer type ofantioxidant are trivalent phosphorous and divalent sulfur-containingcompounds such as sulfides, thiodipropionates and organophosphites.

Antioxidant effectiveness is related to activation energy, rateconstants, oxidation-reduction potential, ease with which theantioxidant is lost or destroyed (volatility and heat susceptibility),and antioxidant solubility.

It has been surprisingly found by the present inventors that onlysynthetic antioxidants stabilize the amorphous lenalidomide. Therefore,suitable antioxidants for use according to the invention are thesynthetic antioxidants. Preferred antioxidants are primary syntheticantioxidants, more preferred are phenolic substituted compounds and evenmore preferred are monophenolic antioxidants, the most preferredantioxidants are BHT or BHA. BHT and BHA interrupt the free radicalchain reaction donating H^(.) to the free radicals formed duringoxidation becoming a radical themselves. These radical intermediates arestabilized by the resonance delocalization of the electron within thearomatic ring and formation of quinone structures.

In the pharmaceutical composition of the invention the syntheticantioxidant is present in an amount of 0.001 to 5% by total weight,preferably from 0.03 to 3% by total weight, even more preferably from0.05 to 0.85 by total weight even more preferred 0.05 to 0.5 by totalweight even more preferred from 0.04 to 0.1% by total weight.

There are different ways of obtaining amorphous lenalidomide. Among themby forming inclusion complexes such as cyclodextrines, adsorbates suchas syloid or by solid dispersions. In a preferred embodiment of theinvention the amorphous lenalidomide is stabilised in a polymer soliddispersion.

The stabilizing of amorphous lenalidomide has been attributed to anantiplasticization effect since solid dispersions typically possesshigher glass transition temperatures than the pure amorphous drug, thusresulting in a lower molecular mobility that prevents phase transition.The stability may also be due to formation of specific drug-polymerinteractions such as hydrogen bonds. Polymers that are commonly used tostabilize the amorphous state in a solid dispersion include but are notlimited to HPMC, HPMCAS, HPMCP, CAP, Eudragit and N-vinylpyrrolidones.Preferred polymers to use in the present invention are pyrrolidones suchas PVP or coPVP.

In a preferred embodiment, the compositions include lenalidomide and thepolymer present in weight ratios ranging from 1:1 to 1:6, from 1:2 to1:5, most preferred from 1:4 to 1:5. Higher ratios give dissolutionproblems.

At least a major portion of lenalidomide, or a pharmaceuticallyacceptable salt thereof, in the composition is amorphous. The term “amajor portion” of lenalidomide, or a pharmaceutically acceptable saltthereof, means that at least 60% of the drug is in amorphous form,rather than a crystalline form. Preferably, lenalidomide, or apharmaceutically acceptable salt thereof, in the solid dispersion is atleast 80% in amorphous form. More preferably, lenalidomide, or apharmaceutically acceptable salt thereof, in the composition is “almostcompletely amorphous” meaning that the amount of lenalidomide, or apharmaceutically acceptable salt thereof, in the amorphous form is atleast 90% as measured by powder X-ray diffraction or any other standardquantitative measurement. Most preferably, lenalidomide, or apharmaceutically acceptable salt thereof, in the composition is in acompletely amorphous form within the detection limits of the techniquesused for characterization.

The excipients to be used in accordance with the present invention arewell-known and are those excipients which are conventionally used by theperson skilled in the art. Depending on the dosage form chosen for thepharmaceutical composition, the person skilled in the art will be ableto select suitable pharmaceutically acceptable excipients. Preferably,the dosage form is an immediate release capsule and the pharmaceuticallyacceptable excipients are chosen from one or more binders, diluents,disintegrants, glidants, lubricants, stabilizers, surface active agentsor pH-adjusting agents. More preferably, the composition of the presentinvention comprises a diluent, a disintegrant and a lubricant.

The diluent to be used in accordance with the present invention may beany diluent known to a person of ordinary skill in the art.Particularly, the diluent to be used in accordance with the presentinvention is an inorganic diluent, polysaccharide, mono- or disaccharideor sugar alcohol. Microcrystalline cellulose or anhydrous dicalciumphosphate is a particularly preferred diluent.

The disintegrant to be used in accordance with the present invention maybe any disintegrant known to a person of ordinary skill in the art.Suitable disintegrants to be used in accordance with the presentinvention are selected from the group consisting of microcrystallinecellulose, croscarmellose sodium, crospovidone or sodium starchglycolate. Croscarmellose sodium and starch are particularly preferreddisintegrant.

The lubricant to be used in accordance with the present invention may beany lubricant known to a person of ordinary skill in the art. Magnesiumstearate is a particularly preferred lubricant.

During preparation and storage of the pharmaceutical compositions of thepresent invention, lenalidomide, or a pharmaceutically acceptable saltthereof, remains in the amorphous form.

The present invention still further provides a process to preparepharmaceutical compositions comprising amorphous lenalidomide, asynthetic antioxidant, a polymer and one or more pharmaceuticallyacceptable excipients.

Lenalidomide and the polymer may be dissolved in the same solvent or indifferent solvents and then combined.

In an advantageous variant of the process of the present invention,lenalidomide or a pharmaceutically acceptable salt thereof is dissolvedin acidic water or a mixture of acidic water and a polar organic solventand, the polymer is added to this solution. Preferred ratio organicsolvent:acidic water is from 8:2 to 1:9, more preferred is 7:3 w/w.Preferred polar organic solvents are alcohols, particularly ethanol ormethanol, ethers, particularly tetrahydrofuran, ketones, particularlyacetone and acetonitrile. Preferably, 0.1N aqueous HCl or a mixture ofacetone and 0.1N aqueous HCl is used. Preferred ratio of acetone: 0.1Naqueous HCl is 7:3 w/w. This ratio gives an optimal impurity profile.

The methods and equipment to carry out the process to form formulationof the present invention are well known in the art.

In one possible embodiment the lenalidomide, or a pharmaceuticallyacceptable salt thereof, and a polymer are dissolved in a suitablesolvent or solvent mixture, then the solvent is evaporated and theobtained mixture is blended with a synthetic antioxidant and furtherexcipients.

Another possible method is adding the synthetic antioxidant asintragranular excipient. The addition of the synthetic antioxidantintragranularly is preferred because the antioxidant is betterdistributed.

In a yet preferred embodiment, lenalidomide, or a pharmaceuticallyacceptable salt thereof, is dissolved in a suitable solvent or solventmixture, the polymer and the synthetic antioxidant are added and thenthe solvent is evaporated to obtain a granule. The granule is densifiedby means of dry granulation, milled and blended with further excipients.

The addition of the antioxidant in the solution has the advantage ofdecreasing the oxidizing compounds in the formula that could come fromthe polymer (such as peroxides), preventing in this way the increase ofoxidative degradation impurities during stability.

The mixtures obtained after blending can be further encapsulated.

Examples of equipments to carry out this evaporation method are fluidbed, high shear mixed and spray drying. When the fluid bed technology isused additionally a pharmaceutical carrier is needed. Lactose,cellulose, starch and phosphates are the preferred pharmaceuticalcarriers. Pregelatinized starch, MCC and calcium phosphate are the mostpreferred pharmaceutical carriers. If MCC is used an extra step todensity the final granules is required. With MCC as carrier a morestable formulation is obtained.

The compositions of the present invention can also be prepared by hotmelting lenalidomide, or a pharmaceutically acceptable salt thereof,with the synthetic antioxidant and optionally adding a polymer. Thisprocess can be carried out without the use of solvents.

The process comprises mixing or granulating the lenalidomide with one ormore pharmaceutically acceptable excipients, followed by encapsulation,using equipment and methods well-known to the skilled artisan. In anadvantageous variant of the process of the present invention, a solutionof lenalidomide, or a pharmaceutically acceptable salt thereof, thesynthetic antioxidant, and the polymer was sprayed over thepharmaceutical carrier e.g. the diluent, in a fluidized bed and theresulting granulate/blend was compacted and milled by dry granulationand finally mixed with one or more pharmaceutically acceptableextragranular excipients, followed by encapsulation. Preferably, asolution of lenalidomide, BHT and co-PVP, in acidic water/acetone wassprayed over microcrystalline cellulose (MCC) in a fluidized bed, afterwhich the granulate/powder blend was compacted and milled by drygranulation and finally mixed with MCC, croscarmellose sodium andmagnesium stearate, followed by encapsulation. Preferably, HPMC orgelatine capsules are used.

In another advantageous variant of the process of the present invention,a solution of lenalidomide, or a pharmaceutically acceptable saltthereof, and a polymer was sprayed over the pharmaceutical carrier e.g.the diluent, in a fluidized bed and the resulting granulate/blend wasmixed with a synthetic antioxidant and one or more pharmaceuticallyacceptable extragranular excipients, followed by encapsulation.Preferably, a solution of lenalidomide and PVP in acidic water/acetonewas sprayed over MCC in a fluidized bed, after which thegranulate/powder blend was mixed with BHT, microcrystalline cellulose orstarch, croscarmellose sodium and magnesium stearate, followed byencapsulation. Preferably, HPMC or gelatine capsules are used.

In a preferred embodiment, lenalidomide form A crystal with an XRPDpattern having peaks at approximately 8, 14. 5, 16, 17.5, 20.5, 24, and26 degrees 2θ is used as starting material for carrying out the aboveprocesses.

The pharmaceutical compositions prepared according to the presentinvention display dissolution behaviour typical for immediate-releaseformulations. The compositions of the present invention exhibit adissolution rate of at least 85% in 15 minutes when tested in 900 ml SGFpH 1.2, pH 2, acetate buffer pH 4.5 or phosphate buffer pH 6.8 in a USPapparatus I at 100 rpm in standard vessels.

The pharmaceutical compositions of the present invention are packaged inblister pack material. The blister pack materials to be used inaccordance with the present invention may be any blister pack materialknown to a person of ordinary skill in the art. Suitable blister packmaterials to be used in accordance with the present invention areselected from the group of Aclar, PVC/Alu, Duplex/Alu, Triplex/Alu andAlu/Alu. To ensure protection of the compositions of the presentinvention from e.g. moisture and thereby preventing polymorphicconversions, Alcar, Triplex/Alu and Alu/Alu are particularly preferredblister pack materials.

After storage of the pharmaceutical compositions in these blister packmaterials for 1 month at 40° C./75% RH, XRPD analysis showed noreflections in accordance with crystalline lenalidomide.

The pharmaceutical composition in accordance with the present inventionmay be used as a medicament. The pharmaceutical composition typicallymay be used in the treatment of multiple myeloma and myelodyplasticsyndromes.

The following examples are intended to illustrate the scope of thepresent invention but not to limit it thereto.

In order to detect the impurities a HPLC with an Analytical column,XSelect HSS T3 (Waters, 150×4.6 mm, dp=2.5 μm) was used. Mobile phase A:phosphate buffer pH 3.5. Mobile phase B: Acetonitrile (ACN).

EXAMPLES Example 1, Lenalidomide:PVP (Weight Ratio 1:4)

The stabilized complex of lenalidomide with povidone has a ratio ofAPI:PVP=1:4 w/w.

-   -   (1) Dissolution: 298.25 grams of povidone are added and        dissolved in 1704 mL of acetone:0.1N HCl (7:3 w/w) solution        under heating (50° C.) and stirring conditions. Once the        povidone is completely dissolved, 74.56 grams of lenalidomide        are incorporated into the dissolution.    -   (2) Spraying: the (1) resulting dissolution is sprayed into a        fluid bed equipment over the filler (972.74 g of anhydrous        dicalcium phosphate) and subsequently dried, obtaining granules.    -   (3) Total mixture: the amounts of the following excipients are        adjusted base on the granulation yield obtained in the previous        step: 277.95 g of microcrystalline cellulose, 51.0 g of sodium        croscarmellose are mixed with the (2) resulting granules. 17 g        of magnesium stearate are sieved through a 0.5 mm mesh and mixed        with the previous blend.    -   (4) This final blend is used to study the influence of the        different antioxidants: no addition, BHT (0.1-0.5%), citric acid        (0.3%-2%), tartaric acid (2-3%) in the following way:        -   (4.1) No antioxidant: Final blend get in step (4);        -   (4.2) 0.1% BHT: 0.01 g of BHT are milled and mixed for 5 min            with 9.99 g of final blend (4);        -   (4.3) 0.5% BHT: 0.05 g of BHT are milled and mixed for 5 min            with 9.95 g of final blend (4);        -   (4.4) 0.3% citric ac: 0.03 g of citric ac are milled and            mixed for 5 min with 9.97 g of final blend (4);        -   (4.5) 2% citric ac: 0.2 g of citric ac are milled and mixed            for 5 min with 9.8 g of final blend (4);        -   (4.6) 2% tartaric ac: 0.2 g of tartaric ac are milled and            mixed for 5 min with 9.8 g of final blend (4);        -   (4.7) 3% tartaric ac: 0.3 g of tartaric ac are milled and            mixed for 5 min with 9.7 g of final blend (4).    -   (5) Different blends are packaged in HDPE bottles (open dish)        and stored 1 week at 55° C./90% RH. Impurities are tested after        this period of time.

Results

No anti- BHT Citric acid Tartaric acid oxidant 0.1% 0.5% 0.3% 2.0% 2.0%3.0% Initial 1 week 55° C./90% RH, Open dish Total Total Total TotalTotal Total Total Total 0.37% 1.01% 0.67% 0.66% 0.97% 0.96% 0.93% 1.12%

Example 2, Lenalidomide:Povidone (Weight Ratio 1:5) without Antioxidant,Different Packaging

-   -   (1) The stabilized complex of lenalidomide with povidone has a        ratio of API:PVP=1:5 w/w.    -   (2) Dissolution: 152.93 grams of povidone are added and        dissolved in 714.6 mL of acetone:0.1N HCl (7:3 w/w) solution        under heating (50° C.) and stirring conditions. Once the        povidone is completely dissolved, 30.59 grams of lenalidomide        are incorporated into the dissolution.    -   (3) Spraying: the (2) resulting dissolution is sprayed into a        fluid bed equipment over the filler (368.46 g of        microcrystalline cellulose) and subsequently dried, obtaining        granules.    -   (4) Total mixture: the amounts of the following excipients are        adjusted base on the granulation yield obtained in the previous        step: 17.25 g of sodium croscarmellose are mixed with the (2)        resulting granules. 5.75 g of magnesium stearate are sieved        through a 0.5 mm mesh and mixed with the previous blend.    -   (5) Capsules: the (4) final blend is then encapsulated into size        0 capsules.

Composition

Lenalidomide 25 mg Povidone K-12 125 mg Microcrystalline cellulose301.18 mg Sodium Croscarmellose 14.10 mg Magnesium stearate 4.7 mgGelatine capsules size 0

Impurities are measured after 1 month in accelerated conditions (40°C./75% RH) in two different packaging material: low protective packaging(PVP/PVDC/Al) and high protective packaging (Al/Al).

Results:

1 month (40° C./75% RH) Initial Al/Al PVC/PVDC/Al Total 0.72% Total0.90% Total 1.65%

Example 3, Lenalidomide:Povidone (Weight Ratio 1:5), AdditionAntioxidant in Different Packaging

-   -   (1) The stabilized complex of lenalidomide with povidone has a        ratio of API:PVP=1:5 w/w.    -   (2) Dissolution: 212.77 grams of povidone are added and        dissolved in 996.56 mL of acetone:0.1N HCl (7:3 w/w) solution        under heating (50° C.) and stirring conditions. Once the        povidone is completely dissolved, 42.55 grams of lenalidomide        and 0.8 g of BHT are incorporated into the dissolution.    -   (3) Spraying: the (2) resulting dissolution is sprayed into a        fluid bed equipment over the filler (431.84 g of        microcrystalline cellulose) and subsequently dried, obtaining        granules.    -   (4) Total mixture: the amounts of the following excipients are        adjusted base on the granulation yield obtained in the previous        step: 80.0 g of microcrystalline cellulose, 24.0 g of sodium        croscarmellose are mixed with the (2) resulting granules. 8.0 g        of magnesium stearate are sieved through a 0.5 mm mesh and mixed        with the previous blend.    -   (5) Capsules: the (4) final blend is then encapsulated into size        0 capsules.

Composition

Lenalidomide 25 mg Povidone K-12 125 mg Microcrystalline cellulose300.71 mg Sodium Croscarmellose 14.10 mg Butylhydroxytoluene 0.47 mgMagnesium stearate 4.7 mg Gelatine capsules size 0

Impurities are measured after 1 month in accelerated conditions (40°C./75% RH) in two different packaging material: low protective packaging(PVP/PVDC/Al) and high protective packaging (Al/Al). Results:

1 month (40° C./75% RH) Initial Al/Al PVC/PVDC/Al Total 0.13% Total0.10% Total 0.33%

Example 4, Lenalidomide:Co-Povidone (Weight Ratio 1:5), AdditionAntioxidant Intragranular

-   -   (1) The stabilized complex of lenalidomide with co-povidone has        a ratio of API:PVP=1:5 w/w.    -   (2) Dissolution: 833.33 grams of co-povidone are added and        dissolved in 3813.88 g of acetone:0.1N HCl (7:3 w/w) solution        under heating (50° C.) and stirring conditions. Once the        co-povidone is completely dissolved, 166.67 grams of        lenalidomide and 3 g of BHT are incorporated into the        dissolution.    -   (3) Spraying: the (2) resulting dissolution is sprayed into a        fluid bed equipment over the filler (1577 g of microcrystalline        cellulose) and subsequently dried, obtaining granules.    -   (4) The obtained granules are compacted using a roller compactor        equipment and subsequently milled through 2 and 0.8 mm screen        size.    -   (5) Total mixture: the amounts of the following excipients are        adjusted base on the milled granules yield obtained in the        previous step: 300.0 g of microcrystalline cellulose, 90.0 g of        sodium croscarmellose are mixed with the (2) resulting granules.        30.0 g of magnesium stearate are sieved through a 0.5 mm mesh        and mixed with the previous blend.    -   (6) Capsules: the (5) final blend is then encapsulated into size        0 capsules.

Composition

Lenalidomide 25 mg Povidone K-12 125 mg Microcrystalline cellulose281.55 mg Sodium Croscarmellose 13.5 mg Butylhydroxytoluene 0.45 mgMagnesium stearate 4.5 mg Gelatine capsules size 0

The invention claimed is:
 1. A pharmaceutical composition, comprising asolid dispersion of amorphous lenalidomide or a pharmaceuticallyacceptable salt thereof in a polymer; a monophenolic antioxidantcompound; and one or more pharmaceutically acceptable excipients;wherein said polymer is PVP or co-PVP and wherein said antioxidant ispresent in an amount from 0.03 to 3% by total weight.
 2. The compositionaccording to claim 1, wherein said antioxidant is dispersed in saidpolymer.
 3. The composition according to claim 1, wherein theantioxidant is BHT or BHA.
 4. The composition according to claim 3,wherein the antioxidant is in a range of 0.05-0.5% by total weight. 5.The composition according to claim 1, wherein the lenalidomide and thepolymer are present in a weight ratio ranging from 1:1 to 1:6.
 6. Thecomposition according to claim 1, wherein the lenalidomide and thepolymer are present in a weight ratio ranging from 1:4 to 1:5.
 7. Thecomposition according to claim 1, wherein said solid dispersion ofamorphous lenalidomide is present in granular form and wherein eachgranule comprises the solid dispersion of amorphous lenalidomide carriedon a diluent.
 8. The composition according to claim 7, wherein saidantioxidant is an extragranular excipient.
 9. The composition accordingto claim 7, which further comprises an extragranular diluent, anextragranular disintegrant, and an extragranular lubricant.
 10. Thecomposition according to claim 9, wherein said antioxidant is BHT or BHAand is contained in said polymer.
 11. The composition according to claim10, wherein said diluent that carries said solid dispersion ismicrocrystalline cellulose.
 12. The composition according to claim 11,wherein said extragranular diluent is microcrystalline cellulose, saidextragranular disintegrant is croscarmellose sodium; and saidextragranular lubricant is magnesium stearate.